Generally, the existing keyboard or keypad equipment for data input should have a sufficiently large size to provide for typing without seeing the keyboard or keypad (herein called a ‘blind’ typing method). This however contradicts to the requirement of having a possible small size for such keyboard or keypad to provide portability of the equipment.
There is known a device for hand entry of discreet information into a computer, described in Inventor's Certificate of USSR No. 1760575, which is considered a closest related art document. A shortcoming of such device is that the maximum number of commands of a five-position joystick, which can be inputted with one movement (impression) of the operator, is ten (five directions of movement plus separation in time). Hence, for input of one symbol (number, letter, or a special character), one should accomplish up to 10-12 movements of the joystick.
In portable data input systems of computers, PDAs, smart-phones, etc., it would be desirable to provide data input by the ‘blind’ method, while accomplishing the input with one hand.